Application note - GPIO on fitlet2 with FC-SCG running Linux

It provides an example of how to use the supported I2C GPIO extender feature of FC-SCG under Linux.

I2C GPIO extender binding and usage

1. Make sure that the kernel you use supports the necessary driver.
Check the following entries in the kernel config:

CONFIG_GPIO_PCA953X=[y]
CONFIG_I2C=y
CONFIG_I2C_CHARDEV=y

2. Make sure that the appropriate I2C bus is enabled in BIOS settings:
Chipset -> South Cluster Configuration -> LPSS Configuration LPSS I2C #[1-8] Support is set to ACPI mode or PCI mode Set LPSS I2C #[1-8] Speed is set to Standard Mode of Fast Mode
NOTE: It’s strongly recommended that all buses are enabled in the range of 1-7